Magnesium neodecanoate

Endpoint summary

Description of key information

In the assessment of magnesium neodecanoate, read-across to the assessment entities soluble magnesium substances and neodecanoic acid is applied since the ions of magnesium neodecanoate determine its fate and toxicity in the environment.

 

Magnesium

As an essential element for living organisms magnesium has a very low potential for toxicity to freshwater as well as saltwater organisms. However, experimental toxicity values are available for several species, although exceeding corresponding OECD test limits:

- an unbounded value of ≥ 500 mg/L NOEC magnesium was identified for microorganisms in activated sludge 

- the lowest inhibitory concentration amounts to 121.3 mg/L magnesium for the green algal species Chlorella vulgaris

- a 48-h LC50 of 140 mg/L magnesium (Daphnia magna) represents the lowest value identified for freshwater invertebrates

- 96h-LC50 values of 541.2, 569.4 and 610.06 mg/L magnesium were determined depending on the magnesium salt used for the freshwater fish Pimephales promelas.

- 48h-LC50 values of 4740 and 2800 mg/L magnesium were determined for saltwater fish species Cyprinodon variegatus and Menidia beryllina, respectively.

 

In sum, magnesium has very low potential for acute aquatic toxicity.

 

Neodecanoic acid

Reliable acute data are available from GLP-conform guideline studies for three trophic levels: algae, invertebrates and fish

- an unbounded value of > 100 mg/L (72h-LL50) was identified for the algae Pseudokirchneriella subcapitata

- an unbounded value of > 457 mg/L (48h-EL50) was identified for the invertebrate species Daphnia magna

- an unbounded value of > 100 mg/L (96h-LL50) was identified for rainbow trout

 

Reliable chronic data are available from GLP-conform guideline studies for two trophic levels: invertebrates and fish

- 21-Day NOEC of 4.78 mg/L neoheptanoic acid (structural analogue) for reproduction of D. magna; Chronic Value (ChV) of 1.7 mg/L (QSAR-based estimate) for daphnids

- 14-d NOEC of 2.22 mg/L neodecanoic acid for growth of Oncorhynchus mykiss; Chronic Value (ChV) of 1.6 mg/L (QSAR-based estimate) for fish

Regarding the toxicity to aquatic microorganisms, a 4-h NOEC of ≥ 200 mg/L for the inhibition of nitrification by microorganisms (Nitrosomonas sp.) is available.

In sum, neodecanoic acid has very low potential for acute aquatic toxicity and a low potential for chronic toxicity.

 

Magnesium neodecanoate

Using existing aquatic toxicity data of the dissociation products of magnesium neodecanoate, the aquatic hazard assessment is based on the most toxic moiety.

 

Regarding acute (short-term) toxicity, the potential is low since relevant EC/LC50 values of magnesium ions and of neodecanoate are above respective OECD test limits.

Regarding chronic (long-term) toxicity, magnesium has very low potential. Existing aquatic toxicity data of neodecanoic acid and neoheptanoic acid are recalculated for magnesium neodecanoate based on a maximum neodecanoate content of 93.9 %.

 

- 21-Day NOEC of 5.09 mg/L for reproduction of D. magna; Chronic Value (ChV) of 1.81 mg/L (QSAR-based estimate) for daphnids

- 14-d NOEC of 2.36 mg/L for growth of Oncorhynchus mykiss; Chronic Value (ChV) of 1.7 mg/L (QSAR-based estimate) for fish

Further, a 4-h NOEC > 213 mg/L for the inhibition of nitrification points to a very low potential for toxicity to sewage sludge microorganisms.